Road traffic accidents are one of the world's largest public health problems. In the EU alone, traffic accidents cause approximately 1.8 million injuries and 43.000 fatalities each year. Many, but not yet all, of today's modern vehicles are provided with active safety systems that may assist the driver in his/her driving. Active safety is defined as technologies that can detect hazardous traffic situations and actively assist road users in avoiding or mitigating accidents. These systems may include for example anti-spin systems but also more sophisticated systems that may assist the driver in controlling the vehicle and monitor the surrounding traffic, such as other vehicles or road users but also other objects or obstacles that may occur on the road. Some of these systems use proximity sensors for monitoring the state of surrounding road and/or users of the road. These active safety systems may for example provide for automatic activation of brakes and/or steering and warn the driver of a registered collision risk.
In US2007/0021915A1, a system for avoiding collisions between a vehicle and another object is described. In this system an information unit comprising a transmitter/receiver is arranged on a host vehicle. The transmitter/receiver transmits and receives radio waves from a transmitter of each other vehicle within transmission range. A position determining device and a processor is further arranged on the host vehicle. The incoming information to the system is analyzed to ascertain whether a collision between the host vehicle and any of the other vehicles is likely to occur. Actions taken by the system could be activation of a driver notification system to alert the driver of the collision risk or activation of a vehicle control system, such as braking or steering of the vehicle to avoid a collision. A drawback with the described system is that it requires that all involved vehicles are provided with transmitter/receivers.
Accidents are often caused by a combination of coincidences, rather than by one single event. Since there are several contributing factors for each accident, this also implies that there are several possibilities for preventing accidents. However, there may occur situations in which a driver of a vehicle has no or very little possibility to act despite an active safety system in the vehicle that may either warn and/or instruct the driver to take action or which automatically takes action to avoid a potential threat to the own vehicle and/or other road users. Further, today the majority of the vehicles that are out on the roads are not equipped with an active safety system. This means that even if one vehicle detects a collision risk with another vehicle, it may not have a possibility to act.
Accordingly, there is a need for improvements in the field of collision warning systems for motor vehicles.